Testicular cancer has a high cure rate if caught early
A study has concluded that one dose of chemotherapy is the best way to cure testicular cancer in many patients.
Doctors already offer either carboplatin or radiotherapy, but scientists needed long-term trial results to see which was the best.
The Medical Research Council project found that the drug offered a similar relapse rate - but far fewer side effects.
A leading expert said it could one day reduce the need for testicle removal.
Several hundred men are diagnosed with testicular cancer each year in the UK.
The vast majority are "seminomas", affecting the sperm-producing cells in the testicle, and almost half of these are caught at an early stage.
These patients have their affected testicle removed, and are then offered either a single dose of carboplatin chemotherapy, a longer regime of radiotherapy, or the option to have no extra treatment with a higher risk of the cancer returning.
Radiotherapy can have severe side effects, while people undergoing this type of chemotherapy can resume their normal lives much more quickly.
The study, led by Southampton University, followed almost 1,500 patients, 904 given radiotherapy, and 573 carboplatin.
The rate of relapse in both groups was roughly the same, and lead researcher Dr Ben Mead said the results were "reassuring" and that carboplatin was the better option.
"Giving patients a carboplatin injection rather than radiotherapy is less unpleasant with fewer long-term risks.
"The initial results of the trial looked encouraging, but we needed to follow patients for another four years before we knew for sure that they had been cured."
Although practice was changing in Europe to include carboplatin, in many other parts of the world, including the US, radiotherapy remains standard treatment, and Dr Mead said he hoped this would now change.
The results are to be presented on Monday at a cancer conference in Birmingham, and Professor Peter Johnson, from Cancer Research UK, said that this cancer had proved to be a "success story" in terms of treatment research.
"This trial shows that chemotherapy can cure early stage seminoma, so that men diagnosed with the disease can be successfully treated with fewer side-effects."
Professor Tim Oliver, from the Bart's and the London Medical School, said that another advantage of carboplatin was that by treating the whole body rather than one area, the small risk of another testicular cancer emerging in the other testicle was also reduced.
This was borne out by the study, which found just two out of 573 patients on carboplatin experiencing this, compared with 15 out of 904 in the radiotherapy group.
He said: "The question now is whether you can approach testicular cancer in a different way, and, rather than remove the whole testicle automatically, carry out a 'lumpectomy' in very much the same way as in breast cancer.
"We are looking for funding to investigate whether this could work."